/*
 * Copyright 2011-2024 GatlingCorp (https://gatling.io)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.gatling.commons.util

final class PushbackIterator[T](it: Iterator[T]) extends Iterator[T] {
  private var pushedbackValue: Option[T] = None

  override def hasNext: Boolean = pushedbackValue.isDefined || it.hasNext

  override def next(): T = pushedbackValue match {
    case Some(value) =>
      pushedbackValue = None
      value
    case _ => it.next()
  }

  def pushback(value: T): Unit = pushedbackValue = Some(value)
}
